Four days before a preschooler died after passing out on a popular space ride at Walt Disney Co.'s Florida park, the company's top theme park executive and two lobbyists had visited the Capitol Hill offices of Rep. Edward J. Markey, D-Mass.

The three wanted to make the case that the kind of federal safety oversight the congressman was proposing for the industry was unnecessary because theme parks were safe and regulated by most states.

Now, 4-year-old Daudi Bamuwamye's death has abruptly put Disney and other theme-park companies on the defensive. The cause of the Pennsylvania boy's death June 13, and whether the Walt Disney World ride had anything to do with it, may not be known for weeks. But the death is galvanizing consumer advocates and safety consultants, who view it as an example of why the kind of federal regulation Markey proposes is needed.

"There may be something we can learn from this incident," said Ken Martin, an independent ride inspector and consultant based in Virginia. "But we can't because there's no federal investigation."

Federal officials lack authority to investigate incidents such as Daudi's death because of an exemption Congress passed in 1981. It allows the Consumer Product Safety Commission to regulate carnival rides because, moving from state to state, they otherwise could escape oversight. Fixed rides at theme parks, however, are exempt.